Timing apparatus



June 14, 1938. F l-LARDY 2,120,407

TIMING APPARATUS Filed sept. 25, 1936 FIG? /N VEN To@ F. HA RD V yATTO/wey Patented June 14, 1938 UNITED STATES Haart? PATENT OF'EQETelephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application September 25, 1936,Serial No. 102,481

7 Claims.

'I'his invention relates to timin-g apparatus and particularly to arestoring means for use with such apparatus.

The invention is applicable particularly to timing apparatus formeasuring intervals of conversation in a telephone system to determinethereby the appropriate charges for the service rendered, such apparatusbeing described, for example, in Patent 2,094,060 issued September 28,1937 to A. J. Busch entitled Timing apparatus.

An object of the invention is the simplification and improvement ofdevices for measuring and indicating intervals of time.

A more specic object of the invention is to provide a restoring forceeifective upon occasion to return the rotating member of timingapparatus to its normal position, which restoring force shall besubstantially uniform regardless of the amount of movement of saidrotating member from its normal position.

In accordance with the arrangement disclosed in the Busch patent,referred to above, means are provided for operating the callingsubscribers register the desired number of times for the initial periodand the desired number of times for each overtime period in accordancewith the requirements for the zone called and the duration of the call,Each timing unit preferably comprises an alternating current motorsuitably coupled to a shaft carrying means for operating in sequence aseries of electrical contacts.

'Ihe motor is preferably o-f the type whose speed depends upon thefrequency of the power supply. By selecting the frequency of the powersupply the shaft controlling the contacts may be caused to make onecomplete revolution in the time interval equal to the initial period forthe zone called and at the termination of the initial period anotherfrequency may be selected to rotate the shaft one complete revolutionfor each overtime period so that all of the charging contacts will beoperated once for the initial period regardless of its duration and willbe operated once during each overtime period.

It will be apparent from the above that in registering the duration of acall the shaft or other driven means controlling the contacts may berotated only a part of a complete turn or it may be rotated severalcomplete turns. It is necessary to provide some means for restoring theshaft to its normal position upon release from the driving force, anobvious means of providing the desired force being to provide a coiledleaf spring, one end being attached to the shaft and the other end beingattached to a stationary member. However, a simple expedient of thisnature is not entirely satisfactory for timing arrangements of thenature referred to above in view of the fact that if the spring is s0tensioned as to provide a sufhcient restoring force when the shaft hasbeen rotated only a part of a complete turn, several turns of the shaftwill cause an undesirable amount of tension n the spring and may resultin breakage thereof.

According to a feature of the present invention, the restoring spring istensioned only during a part of the first rotation of the shaft, meansbeing provided whereby this force is stored in the spring duringcontinued rotation of the shaft.

In accordance With a specific embodiment of the invention, one end ofthe coiled leaf restoring spring is attached to the shaft while theother end is attached to a casing which encloses the spring. When theshaft starts its rst rotation, the casing remains stationary, resulting,of course, in an increase in the tension of the spring. However, asrotation of the shaft continues, an arm carried thereby comes in contactwith an arm projecting from the casing, this engagement being effectiveto cause the casing` to be rotated with the shaft whereby additionaltension is not added to the spring. A special adjustable connectionbetween the casing and its support permits this rotation but at the sametime provides sufficient restraint to maintain the casing stationaryduring the initial part of the rotation of the shaft. A completeunderstanding of the operation of the arrangement contemplated by theinvention as well as an appreciation of the Various advantageousfeatures will be gained from considerationof the following descriptionin connection with the drawing, in which:

Fig. 1 shows schematically a timing arrangement of the type contemplatedby the invention as well as a part of a dial telephone system With whichthe invention may advantageously be used;

Fig. 2 is a perspective view of the driven gear and the restoring meansof a timing unit of the nature contemplated by the invention, a part ofthe spring casing being broken away to disclose the restoring spring;

Fig. 3 is an exploded View of the assembly shown in Fig. 2;

Fig. 4 is a front elevation of the unit, the driven gear having beenrotated a part of one complete rotation from normal retracted position;and

Fig. 5 is a view similar to that of Fig. 4, the gear having been rotatedan additional amount.

Referring now to the drawing, Fig. l shows schematically a portion of adial telephone system of the cross-bar type utilizing a universal timingmechanism of the general type, described in the Busch patent referred toabove, the arrangement utilizing the restoring means of the presentinvention. For a more detailed blisclosure of the circuits involved insuch a system reference may be had to Patent 2,089,438 issued August 10,193'7, to F. J. Scudder, entitled Telephone systems.

The timing unit disclosed comprises a synchronous motor 2| capable ofoperating with a'power supply varying in frequency with the speed of themotor being directly proportional tothe applied frequency. The motorshaft 22 has a-slidable driving pinion 23 adapted when relay 21 isenergized to engage gear'28 to rotate the `cam shaft 29counter-clockwise. Shaft 29, `due Yto suitable means which will bedescribed later and which includes a spiral spring 3| is biased to adefinite zero .position with lug 32 on gear 28 pressed against thespring stop 33. Motor 2| and the gearing between shafts 22 and 29 arechosen so that, for a typical example, shaft 29 makes one completerevolution in five minutes when the motor is supplied with a frequencyof twelve cycles per second and one revolution in four minutes with apowersupply frequency of fifteen cycles. Other frequencies mayof coursebe employed to give other desired time intervals.

Shaft 29 carries the necessary cams for controlling the various timingand registering circuits, two of these cams, 4| -and 42, being shown.Relay 43 is associated with the trunk circuits and operates, asexplainedin the Busch patent above referred to, upon response of thecalled subscriber. Relay'46is adapted to operate after the timingarrangement has been in operation for a predetermined periodoftimethisrelay may be controlled, as described in the Busch'patent,through an overtime cam carried by shaft 29.

The manner in whichthe timingunit operates for timing a'particulartelephone call will now'be explained in connection with the portion of`a cross-bar dial telephone system disclosed in Fig. 1.

'Operation of relay 43 upon response of the called subscriber completes`an energizing circuit forrelay 21 traced rfrom battery'41,winding ofrelay 21, make contact of relay 431to Vground 41, relay 21 operatingover this circuit. Operation of relay 21 (1) moves armature'4'8fto slidepinion 23 into engagement withfgear 28 and '(2) connects frequencysource 49 (f1), which we will'assume to be twelve'cycles per second,todriving motor 2|. Motor 2|, therefore,startsrotating shaft v29 at theinitial rate'(onerotation in ve minutes) to measure the duration'ofthe'telephone connection.

As soon as shaft`29` begins to'turn'to time'the initial period ofveminutes, holding cam 4| `on shaft 29 closes contacts5l'to establish anobvious holding circuit for relay 21,which holding circuit is due toground 52 under the control of the calling subscriber.

Each rotation ofcam42 causes, through operation of contacts 53,transmission ofa current impulse to the calling subscribers messageregister.

After operation of the 'arrangement for a predetermined time, relay 48is operated under control of a suitabletime measuring devicegfor eX-ample, a cam carriedfby shaft-29, thereby disconnecting -frequencysource 49 :from motor i2 i action of coiledy spring 59.

and connecting frequency source 56 (fz) thereto, it being assumed thatthe frequency of this source is fteen cycles per second. The shaft willnow be rotated at the rate of one revolution in four minutes therefore.5

When the telephone connection has ceased and the calling party has hungup, the called station supervisory relay 43 will be released and theholding circuit for motor relay 21 will be opened since the ground overcontacts 5| is under the control of the calling party. The consequentrelease of relay 21 opens the power supply circuit for motor .2| anddisengages pinion 23 from gear 28 allowing shaft 29 to rotate clockwiseunder the action of restoringspring 3| to cause shaft 29 to assume itsnormal position with lug 32 against spring stop 33. The timing unit isnow ready for usefor another call either to the same zone or a differentzone and further details of the operation of the timing unit may besecured by reference to the above-mentioned patent of A. J. Busch.

'I'he action of restoring spring 3| and associated parts of therestoring mechanism with which the invention is particularly concerned4will now Ibe described with reference to Figs. 2, 3, 4 and 5.-

Referring now to Figs. 2 and 3,*a hollow shaft |30 is, as shown,attached to gear lwheel 28, this shaft terminating in a round shoulderedportion |3|. Shaft 29 is attached to the opposite side'of '30 gear wheel28. A shaft |32 is adapted to t within hollow shaft |30, a portion of itprojecting therefrom'at the end remote from gear lwheel 28. A disc |33is rigidly attached to shaft |32.

Spring casing |31, in the form of a shallow cylinder closedat one end,is adapted'tobe positioned on shaft |32 with its closed end abuttingdisc |33 as shown most clearly in Fig. :2. A

'toothed coupling |38 is attached to the closed kend tion |3| and theother end of the spring beingipositioned in slot |42 provided in 'casing|31. An arm l|43 is attached to casing 31 and projects therefrom, beingengaged upon occasion'by arm |44, which is carried by shaft |30. *.50

Toothedcoupling'l39 is attached to shaft t|32 by means of pin |41,whichis adapted to be posivtioned in'hole'l48 provided in shaft |32. By.vir- `tue ofthe elongated aperture |49, lateral movement withinlimits'of toothedcouplingl 39' is per- (.55

. mitted, it'being normally held in engagement with toothed couplingi138, 'l1owever,due' to the biasing Acollar|5| adjustably held on shaft|32 by screw`|52 serves toihold springilll'in` place on'the shaft andto'regulate m0 the biasing force'of the spring.

lFor convenience of illustration,`the assembled unit is shownmounted on.a suitable upright |58, screw-|59 passing through an aperture'thereinand engaging threaded end portion '|6| of shaft 1,05

`Shaft 29 Ywhich is attached to' wheel 28 extends throughaperture |62provided in upright |63. A bushing |64 is'positioned on shaft 29 Vandserves to retain the'parts'in proper assembled po- -sition on shaft |32.A washer |61 may be pro- 70 vided to eliminatefriction between gearwheel '28 and upright |63 and to provide proper spacing.

Shaft |32 and parts integral therewith are therefore rigidly attached'tosupport |58, while gear wheel-28 and partsintegralttherewith are rotat-15 able about shaft |32. The supporting arrangement actually used maybe, however, of any type consistent with the operation of other parts ofthe mechanism.

In order to further describe the restoring arrangement, let us assume,referring to Fig. 2, which shows the parts in their normal position,that gear wheel 28 be engaged by drive gear 23 (Fig. l) `and rotated ina clockwise direction. Shaft |33 being integral with gear wheel 28 is,of course, rotated also and, as one end of spring 3| is attached toshouldered portion |3| through engagement in slot |4| rotation of thegear wheel winds up the spring, the other end of which is attached tospring casing |37 which is restrained from rotation at this time due tothe frictional engagement of toothed couplings |38 and |39. The tensionof spring |53 is so fixed by adjustment of collar |5| that there issuiiicient friction between the adjacent edges of the two toothedcouplings to hold the spring casing against rotation.

However, after rotation of gear wheel 28 for a predetermined distance,for example, three-quarters of a rotation, the position illustrated inFig. 4 is reached wherein arm |44, whichis rotated with shaft |30, isbrought into engagement with arm |43 attached to spring casing |31.During this time the tension of spring 3| had been increased from thepredetermined initial tension to the maximum desired tension, a rangewhich may be, for example, from. an initial tension of 40 inch grams toa maximum tension of 60 inch grams. Should the gear wheel be-releasedfrom the driving force during any part of this rotation, therefore,spring 3| has sufficient tension to restore the mechanism to normalposition. On the other hand at no time, even when the maximum of 60 inchgrams has been reached, is the tension objectionably large. However, asubstantial increase over this maximum value would be objectionable froma friction standpoint and might result in breakage of the spring, and asthe gear wheel Z3 may be rotated several turns before completion of thecall, it is desirable that means be introduced for preventing furtherincrease in the tension of spring 3|, retaining at the same time thetension already stored therein against the time at which the energy willbe needed for restoring the mechanism to normal position.

Referring again to Fig. 4, as rotation of gear wheel 23 continues,engagement of arm |44 with arm |43 will be effective to cause rotationof spring casing |31, toothed coupling |39 being cammed back against theforce of spring |50, as

shown in Fig. 5, and allowing relative rotation of the two toothedcouplings |39 and |38.

In this manner after the desired maximum tension of spring 3| has beenattained, continued rotation of gear wheel 28 results merely incorresponding rotation of spring casing |31, thereby preventing anyincrease above the maximum point in the tension of the spring regardlessof the number of rotations of the gear wheel. Immediatel5T upon releaseof the mechanism, however, the energy stored in the spring is effectiveto restore the parts to normal position.

While .a specific embodiment and one particular application ofapplicants invention have been described, the invention is not limitedto the specific embodiment nor to the specific application described.For example, while a shaft has been disclosed for operating the timingcontacts other Contact operating means may be used such as cams on theface of the gear wheel of the general nature described in the copendingapplication of E. D. Mead, Serial No. 68,073 filed March 10, 1936.Further, the invention may be used in connection with other types oftelephone call timing systems or in connection with timing arrangementsfor general use, so that the embodiment and application described shouldbe taken as illustrative of the invention and not as restrictivethereof.

What is claimed is:

1. A timing mechanism comprising a rotatable driven member biased to adenite normal position, a driving member, means for engaging said drivenmember and said driving member, a coiled spring eiective afterdisengagement of said members for restoring said driven member to itsnormal position, one end of said coiled spring being fastened to saiddriven member, rotatable means fastened to the other end of said coiledspring, means for preventing said rotatable means from rotating to anysubstantial extent in one direction while permitting its rotation in theother direction when the applied force exceeds a definite minimum, therotation of said driven member tending through said spring to rotatesaid rotatable means in said other direction and positive driving meanscarried by saiddriven member for causing rotation of said rotatablemeans in said other direction.

2. A timing mechanism comprising a rotatable driven member biased to adenite normal posii tion, a driving member, means for engaging saiddriven member and said driving member, a coiled spring effective afterdisengagement of said members for restoring said driven member toitsnormal position, one end of said coiled spring being fastened to saiddriven member, a drum, mounting means for said drum preventing rotationof said drum to any substantial extent in one direction while permittingits rotation in the other direction when the applied force exceeds adefinite minimum, the other end of said coiled spring being fastened tosaid drum, the rotation of said driven membertending through said springto rotate said drum in said other direction and positive driving meanscarried by said driven member for causing rotation of said drum in Saidother direction. Y

3. A timing mechanism comprising a rotatable driven member biased to adefinite normal position, a driving member, means for engaging saiddriven member and said driving member, .a drum mounted for rotation inone direction while incapable of being rotated in the opposite directionto any substantial extent, spring means mounted on a xed axis forresisting the rotation of said drum in said one direction until theapplied force has .exceeded a denite minimum, a spiral spring effectiveafter the disengagement of said members for restoring said driven memberto its normal position, one end of said spiral spring being rotatablewith said drum and the other end being rotatable with said driven memberand positive driving means carried by said driven member for causingrotation of said drum in said one direction.

4. A timing mechanism comprising a rotatable driven member biased to adefinite normal position, a driving member, means for engaging saiddriven member and said driving member, a drum mounted for rotation inone direction, a toothed coupling carried by said drum, a second toothedcoupling, means for normally holding said second toothed coupling inengagement with said first toothed coupling, engagement of the twotoothed couplings being eiective to yieldably restrain said drum from.rotation in said one direction and to prevent rotation of said drum inthe opposite direction to any substantial extent, a spiral springeffective after the disengagement of said driven and driving members forrestoring said driven member to its normal position, and positivedriving means effective after rotation of said driven member for apredetermined amount for causing rotation of said drum in said onedirection against the yieldable restraint of said couplings.

5. A timing mechanism comprising-a rotatable driven member biased to adenite normal position, a driving member, means for engaging said drivenmember and said driving member, a drum mounted for rotation in onedirection, a toothed coupling carried by said drum, a second toothedcoupling, means for urging said second toothed coupling into engagementwith said first toothed coupling, engagement of said couplings beingeffective to yieldably restrain said drum from rotation in said onedirection and to prevent rotation of the drum in the opposite directionto any substantial extent, a spiral spring effective after thedisengagement of said driven member and said driving member forrestoring said driven member to its normal position, one end of saidspring being fastened to said driven member and the other end beingattached to said drum whereby relative rotation of said driven memberand said drum tends to add tension to said spring, and means effectiveupon said spring reaching a predetermined tension for providing apositive drive connection between said driven member and said drumwhereby additional rotation of said driven member will cause rotation ofsaid drum against said yieldable restraining force.

6. A timing mechanism. comprising a rotatable driven member biased to adefinite normal position, a driving member, means for engaging saiddriven member and said driving member, a drum mounted for rotation inone direction, a toothed coupling carried by said drum, a second toothedcoupling, means for urging said second toothed coupling into engagementwith said rst toothed coupling, engagement of said couplings beingeffective to yieldably restrain said drum from, rotation in said onedirection and to prevent rotation of the drum in the opposite directionto any substantial extent, a spiral spring effective after thedisengagement of said driven member and said driving member forrestoring said driven member to its normal position, one end of saidspring being fastened to said driven member and the other end beingattached to said drum Whereby relative rotation of said driven memberand said drum tends to add tension to said spring, means effective uponsaid spring reaching a predetermined tension for providing a positivedrive connection between said driven member and said drum wherebyadditional rotation of said driven member will cause rotation of saiddrum against said yieldable restraining force, and means for adjustingsaid yieldable restraining force.

7. A timing mechanism comprising a rotatable driven member biased to adefinite normal position, a driving member, means for engaging saiddriven member and said driving member, a drum mounted for rotation inone direction, a toothed coupling carried by said drum, a secondtoothedv coupling, means for urging said second toothed coupling intoengagement with said first toothed coupling, engagement of saidcouplings being effective to yieldably restrain said drum from rotationin said one direction and to prevent rotation of the drum in theopposite direction to any substantial extent, a spiral spring effectiveafter the disengagement of said driven member and said driving memberfor restoring said driven member to its normal position, one end of.said spring being fastened to said driven member and the other end beingattached to said drum whereby relative rotation of said driven memberand said drum tends to add tension to said spring, an arm carried bysaid driven member, an arm carried by said drum, said arms being sopositioned with respect to each other that they are brought intoengagement after relative rotation of said driven member and said drumof a predetermined amount, engagement of said 'arms being effective toprovide .a positive drive connection between said driven member and saiddrum whereby additional rotation of said driven member will causerotation of said drum against said yieldable restraining force.

FRANK HARDY.

